OBD-II code · Powertrain (generic)
P040E EGR Temperature Sensor A Circuit Intermittent/Erratic
EGR temperature sensor A signal jumps or drops out intermittently. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
Is it safe to drive with P040E?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIntermittent connector
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- Parts involved
- Egr Temperature Sensor
Related codes
- P040AEGR Temperature Sensor A Circuit
- P041EEGR Temperature Sensor B Circuit Intermittent/Erratic
- P040BEGR Temperature Sensor A Circuit Range/Performance
- P040CEGR Temperature Sensor A Circuit Low
- P040DEGR Temperature Sensor A Circuit High
- P040FEGR Temperature Sensor A/B Correlation
- P0410Secondary Air Injection System Malfunction
- P0411Secondary Air Injection System Incorrect Flow
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.